In the art of gas-liquid chromatography (GLC), it is necessary to prepare packed columns as well as coated capillary tubes which are employed in conjunction with a suitable detector instrument, gas chromatograph, for obtaining analytical data relative to chemical compositions of a highly complex organic substance e.g., essential oils, perfumes, flavors, etc. The preparation of a packed column involves firstly, coating a suitable particulate packing support with a layer of stationary phase chemical, drying the coated support, and then transferring the coated and dried packing into a column of desired dimension in a manner such that the packing material is uniformly or homogeneously distributed throughout the column. The preparation of capillary tubes involves firstly, cleaning a tube with various solutions and then coating the walls thereof with a layer of stationary phase chemical.
In the case of gas-solid chromatography (GSC), the wide bore columns of desired dimension are packed with an inert solid support, such as, Chromosorb porous polymer beads.
Various packing supports and stationary phase chemicals are well known in the gas chromatography art. Typical packing supports include inert materials such as diatomaceous earths, glass beads, polymer beads, crushed fire brick and the like. Stationary phase chemicals include polyesters, polyethylene glycols, methyl and phenyl silicones, substituted silicones as well as many other chemicals.
Various techniques and devices are known in the prior art for performing individual steps involved in the preparation of columns and capillary tubes. For example, U.S. Pat. No. 3,513,562 describes a fluidized drying device for drying coated packing support materials. The use of capillary tubes coated with stationary phase materials is described in U.S. Pat. No. 2,900,478. Vibrating devices, for example, are known for the purpose of assisting in the uniform packing of gas chromatography (GC) columns. While the various prior methods and means are operable to produce packed columns and capillary tubes which may perform adequately for many applications, there has remained a need to maximize efficiency of the entire procedure for preparation of columns and capillary tubes such that the time and expense of preparing such means for use in gas-solid and gas-liquid chromatographic analyses might be substantially reduced. There has also remained prior to this invention a need for preparing packed columns with a very large number of theoretical plates and capillary tubes which will yield more highly consistent and reproducible analytical results.
It is important to properly condition the packed and capillary columns before using them for analysis of the complex mixture of organic compounds. In the prior art, while conditioning the columns, one end of the column is connected to the inlet of the carrier gas whereas the other end is left open to the atmosphere by not connecting it to the detector inlet which otherwise would contaminate the detector system. Thus, in order to meet the aforementioned pre-requisite, very expensive and highly sophisticated gas-chromatograph units are employed thereby increasing the time and expense of preparing such columns for satisfactory use in gas-solid and gas-liquid chromatography. Hence, there has been a great need for a column pre-conditioning means that would be more efficient, and economical to achieve this desired end.